In general, exhaust gas discharged from an engine of a vehicle includes CO, HC, NOx, and the like, which are harmful to humans. As a post-processing device that oxidizes or reduces the harmful exhaust gas to convert the harmful exhaust gas into CO2, H2O, N2, and the like, which are harmless to humans, a catalytic converter is provided in an exhaust system in the vehicle.
Recently, in order to meet exhaust gas regulations that have gradually become stricter, a warm up catalytic converter (WCC) post-processing device is applied which is a catalytic device with high purification efficiency that may effectively oxidize SOF components as well as CO components and HC components that are included in the exhaust gas.
Here, the WCC post-processing device is constructed such that an inlet and an outlet are opposite to each other at both sides of a case having a cylindrical shape. A carrier, which oxidizes various harmful components included in the exhaust gas, is mounted in the case, and a mat is interposed between the carrier and the case.
For example, the WCC post-processing device is configured in an exhaust system of a turbocharged engine, and the WCC post-processing device of the exhaust system of the turbo engine is provided with a gasket that fastens an exhaust flange and a turbo flange by means of studs when the gasket is interposed between the exhaust flange and the turbo flange, thereby sealing the exhaust gas leaking between the exhaust flange and the turbo flange.
As one example of the gasket in the related art, the gasket has a sealing structure in which metal plates are disposed to face each other at an interval, a plurality of stud holes, which the studs penetrate, is provided in the metal plates, and mica, which is a non-metallic material, is interposed between the metal plates.
Here, in the gasket, a portion around the stud holes to which the studs are fastened may be defined as a fastening portion, and a central portion around an exhaust gas passage through which the exhaust gas passes may be defined as a sealing portion.
However, the gasket in the related art has a problem in that the exhaust gas frequently leaks because of a collapse of the mica material at the sealing portion between the metal plates, a decrease in surface pressure at the fastening portion, and the occurrence of cracks in the fastening portion. In particular, because a stay, which fixes the warming up catalytic converter to a vehicle body, is formed to have a hard structure, bolts are loosened or the sealing portion of the gasket is deformed, which may cause a leak of the exhaust gas.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.